This invention relates to a new and improved apparatus and process for producing a new and improved continuous and endless ceramic or synthetic fabric from glass, graphite, boron, quartz, aramid (e.g. Kevlar), nylon, saran, polyester, polyolefine, etc.; the fabric of this invention has a weave oriented at a bias to the fabric length.
These ceramic and synthetic fabrics are used as a reinforcement for structural elements which are subject to a variety of stresses, particularly torsion stresses; frequently, the stresses are produced along the length of the applied fabric. Since the usual orientation of a fabric weave is perpendicular (i.e. 90.degree.) to the fabric length, it is customary to convert the 90.degree. fabric weave to a bias orientation. This conversion involves cutting or slitting a fabric such as graphite diagonally along the length into sections which are then reassembled and sewn together into a continuous fabric which is biased along its length.
This method of reassembling the graphite fabric sections is time consuming and also, some material is lost due to the geometry of reassembly. In addition, when the sections are sewn back together, this requires extra labor, and more time is lost; also, the join lines due to the sewing become lines of weaknesses in the reassembled fabric.
There is required an apparatus and process for converting a ceramic or synthetic fabric from a 90.degree. weave to a bias orientation without the time consuming and expensive steps involved in the prior method. Also, it would be desirable to produce a one-piece, endless, bias cut, graphite fabric without the presence of join lines.
Take up roll systems that produce tubular fabrics for use as belts are known (e.g. U.S. Pat. No. 2,672,163) but do not provide a sufficiently uniform weave which is imperative if the ceramic fabric is employed as a reinforcement for structural members. Fairly complicated machines such as described in U.S. Pat. No. 3,426,804 to R. M. Bluck have been designed to produce bias weave fabrics, but that particular machine forms a narrow strip (about 6") of bias woven fabric having a heavy weave. Furthermore, the machine itself is extremely cumbersome and expensive, and it would be very difficult and costly to increase the strip width capacity.